Fluid dispensing head assemblies, whether they are used for dispensing or depositing hot melt adhesives, plastic extrusion materials, cosmetic lotions, or the like, are of course well known. Such fluid dispensing head assemblies, such as, for example, hot melt adhesive dispensing head assemblies, normally comprise filter mechanisms or components which are disposed within a filter block to which a hot melt adhesive supply conduit is fixedly connected. More particularly, the filter mechanism or component is conventionally disposed within the filter block immediately downstream of the fluidic connection defined between the hot melt adhesive supply conduit and the filter block.
While such filter component or mechanism therefore filters or entraps most particles or debris whereby such debris or particles do not contaminate the hot melt adhesive, debris or particles as small as, or smaller than, 0.005 inches sometimes find their way or migrate through the system, ultimately clogging or blocking nozzles which may have small orifices on the order of 0.010-0.015 inches in diameter. Such particles can be released, for example, during primary filter change operations whereby stagnant debris disposed around the filter component may be dislodged or otherwise stirred up or released, or alternatively, such particles can be formed within the adhesive head assembly after the primary filtration has taken place within the aforenoted filter block upstream and remote from the dispensing valve assembly nozzle. Regardless of how such particles or debris are formed or find their way into the adhesive dispensing system, it is desirable to catch or entrap such particles before they enter the dispensing valve assembly nozzle.
A need therefore exists in the art for a removable inline nozzle filter which can effectively be incorporated within the dispensing valve assembly at a position or location immediately upstream of the dispensing nozzle so as to catch, filter, or entrap any particles or debris which may nevertheless still be present within the system despite previous filtration of the hot melt adhesive within the conventional filter block assembly at a position or location upstream and remote from the dispensing nozzle.